1. Save around 20,000 diamonds for Special Shop (expected once every couple months) where you can get tons of huge discounted items, and event rare ones like Limited SSR (at 3,000 diamonds each) and SSR+ (at 7,500 diamonds each) relics.
2. Summon 10 elite for 2,700 diamonds only at early game for SR and SR+ angels.
3. Buy Epic scrolls for 1,500 diamonds each from Diamond store once you are abundant with SR+ and aiming for SSR.
4. Buy Battle Quick Combat times until 30/60 and 100 diamonds during summon events for more event items.
5. Buy keys or lucky coins during Lost Sanctuary or Lucky Valley.
6. Buy Clash of Titans first 3 attempts for 10 diamonds each and win for 15 diamonds each (profit of 5 each win).
7. Buy Sky Tower keys, 1 or 2 times a day when you have passed 300 stages, or earlier if you want to rush. Especially buy more when it is double rewards Sky Tower event.
8. Buy Dragon Wish amulets at 500 diamond each if you want to speed up Orange Attire collection. Once you have full Orange Attires you can buy Dragon Scales to upgrade them (only for super VIPs)
9. Buy Relics for 3,000 diamonds from Mystery shop in Abyss only if you really need it (like Sky Dome for Chaos).
10. Revive in Abyss for 50 diamonds if you can win more stages (especially bosses).
(Created by AM-55 CuteAngels)